The invention relates to scroll compressors, and more particularly to a retainer structure for a compressor check valve.
Scroll compressors are widely used in refrigerant compression applications. A scroll compressor typically includes two interfitting scroll members. Each scroll member has a base with a generally spiraling scroll wrap extending from the base. The wraps interfit to define a plurality of compression chambers. One scroll member acts as a non-orbiting scroll member and maintains a fixed position while the other scroll member acts as an orbiting scroll member and rotates relative to the non-orbiting scroll member. The relative rotation causes the wrap in the orbiting scroll member to orbit relative to the wrap in the non-orbiting scroll member, changing the volume of the compression chambers. This changing volume compresses refrigerant trapped in the compression chambers.
When the compressor is shut down residual pressure caused by compressed gas trapped between the wraps and contained within other compressor components, such as in a discharge plenum, discharge lines and/or a condenser, may drive the orbiting scroll in a reverse direction. This reverse rotation may continue until pressures on the high pressure side of the system equalize with pressures on the low pressure side of the system. This prolonged reverse rotation is undesirable.
To minimize or prevent reverse rotation from occurring, scroll compressors often have a check valve that moves between an open position and a closed position. The check valve opens when the compressor is compressing refrigerant, but quickly closes when the compressor shuts down. The check valve therefore prevents the flow of compressed refrigerant back into the compressor chambers upon shutdown, limiting the amount of trapped gas communicating with the compression chambers and reducing the occurrence of reverse rotation.
If the check valve is a disc-type check valve, a check valve retainer keeps in the check valve within a discharge cavity. The check valve retainer may be held in the non-orbiting scroll member via an interference fit, but interference fits often require precise tolerances to ensure proper seating of the check valve. If there is too little interference between the check valve and the bore, the check valve retainer tends to unseat itself, but too much interference may cause distortion of the non-orbiting scroll.
There is a desire for a check valve retainer structure that reliably fits into the non-orbiting scroll.
Accordingly, the present invention is directed to a scroll compressor having a check valve retainer with a retaining lip that keeps the check valve retainer in a scroll. The retaining lip fits into a recess formed on an inner wall of a discharge cavity in the scroll. To attach the check valve retainer to the scroll, an expansion fit locking member having a protrusion forces a portion of check valve retainer wall into the recess. The retaining lip ensures that the check valve retainer stays attached to the scroll without risking scroll deformation.
In an alternative embodiment, the retaining lip is manufactured as an integral part of the check valve retainer. The check valve retainer is then press fit into the scroll, allowing the retaining lip to flow into the recess. Other possible embodiments include separate locking devices that wedge the retainer into the scroll.